Pen tip automatic retraction



May 4, 1965 R. P. DANNEBAUM PEN TIP AUTOMATIC RETRAGTION Filed Sept. 20,

Fig. 2,

M m R 7 31% i w M N D e, p. I

United States Patent 3,181,567 PEN TIP AUTOMATIC RETRATIGN Rex P. Dannebaum, 45-971 Towne Ave, indie, (Ialii. Filed Sept. 2%, 1962, Ser. No. 225,065 2 Claims. (Ci. 120-4203) This invention relates to the general field of writing instruments, and more particularly concerns the actuation of writing tips, as for example pen ball points, to vary the exposure thereof in response to finger or thumb pressure applied to the instrument.

A continuing problem presented by conventional commercial ball point pens is that of inadvertent marking of a shirt or coat pocket when the pen is replaced therein without prior retraction of the pen tip. Past attempts to solve this problem have included the provision of Washable inks, which nevertheless, do not solve the problem of initial unsightly marking of the shirt or coat.

The main object of the present invention is to provide a solution to the unwanted marking problem, through the creation of an automatically retracting pen point or tip characterized in that the tip is exposed for writing only when the users hand grips the pen casing during writing. As broadly conceived, this result may be brought about by providing a writing tip which is movable proximate the terminal of the housing to vary the tip exposure, and means for actuating tip movement and being locally exposed at the side of the housing to be actuated by the users finger or thumb during writing. Typically, such means includes a finger or thumb pressure responsive element which projects through an opening in the side of the housing proximate the tip.

An additional object of the invention is to provide for the realization of the aforementioned main object through providing a novel actuating means the construction details of which are particularly adapted to the results desired. Thus, the actuator is constructed to advance a cartridge within the shell for increasing the exposure of the tip and also preferably acts to continually urge the cartridge in a retraction direction for immediately retracting the I tip when the pressure responsive element is released. Typically, the pressure responsive element is movable generally transversely with respect to cartridge axial movement, and novel coupling mechanism is provided to convert the transverse movement of the pressure element to axial movement of the cartridge and writing tip, all within the limited confines of the pen housing.

These and other objects of the invention, as well as the details of certain illustrative embodiments, will be understood more fully from'the following detailed description of the accompanying drawing, in which:

FIGS. 1 and 2 are axial sections showing one form of the invention wherein the writing tip is retracted and advanced; and I FIGS. 3 and 4 are axial sections showing another form of the invention wherein the writing tips are retracted and advanced.

In FIGS. 1 and 2 the elongated pen housing is shown at it with an opening 11 within which a writing tip 12 is movable proximate the terminal of the housing to vary the exposure of the writing tip. The means for actuating the tip movement is generally shown at 13 and may be considered as having a portion thereof which is locally accessible at the side of the housing It to be actuated by the users hand during writing. Such portion typically includes a finger or thumb pressure responsive element 14 projecting through the side opening 15 in the housing in proximity to the tip 12, considering the overall length of the pen housing.

The means 13 may be considered to include in one of its forms an elongated cartridge generally indicated 3,181,5fi7 Patented May 4,1h

at 16 which is attached to the writing tip 12, typically for supplying writing fluid thereto, the cartridge also being movable axially within the shell or housing 19 to vary the exposure of the tip with respect to the opening. The actuator may also be considered to include mechanism operatively coupling the element 14 to the cartridge for axially advancing the latter in response to transverse movement of the element 14. Typically,'the coupling mechanism shown includes a bell crank 17 pivoted at 18 so that one arm 19 of the crank coupled to the element 14 as by pivot 26 moves generally inwardly into the shell interior 21 as the other arm 22 of the crank coupled to the cartridge moves generally axially within the shell. The coupling of the arm 22 to the cartridge 16 is shown in this form of the invention to include one or more hangers .23 the ends of which are pivotally coupled at 24 and 25 to the arm 22 and the cartridge collar 26, respectively.

FIG. 2 shows the pressure element 14 actuated by the users finger or thumb 4t? and the cartridge advanced to the extent that the writing tip is fully exposed. Under these conditions the terminal of the cartridge flange 27 bottoms against the interior shoulder 2% of the pen housing, limiting such forward advancement. The crank 17 in FIG. 2 resists retraction of the cartridge, since pivot 18 is in near axial alignment with pivot 20. If desired, a stop 29 may be provided within the housing interior to limit inward displacement of the pressure element 14, as shown in FIG. 2.

The actuator means may also be considered as continuously urging the cartridge in a retraction direction for decreasing the exposure of the tip 12. As an example of this, the actuator means is shown to include a spring 3i) received on the cartridge inwardly of the ele ment 14 and compressed between the shoulder 28 and the part 31 of the cartridge.

Referring now to FIGS. 3 and 4 the only difference from the previously described structure is found in the type of actuator mechanism for coupling the pressure element 14 to the cartridge. Such modified mechanism is shown to include a cam 33 carried by the pressure element 14 and a follower 34 carried by the cartridge and actuated by the cam as the latter moves inwardly to the position shown in FIG. 4. Such movement urges the follower and the cartridge to increase the exposure of the tip 12. Also, the actuator means is shown as pivoted at 35 so that the cam and pressure elements swing inwardly about the pivot in response to finger pressure. The actuator spring 30 acts as previously described to urge the cartridge in a retraction direction, and by increasing the exposure "of the pressure element 14 at the side of the pen casing.

FIG. 4 also shows the cam to have a plateau 36 acting to resist axial retraction of the follower and cartridge, without completely blocking such retraction. Accordingly, the actuator mechanism acts to hold, or assists in holding, the tip 12 in protruding condition.

I claim:

1. In a writing pen assembly, the combination com prising an elongated shell having an end opening, an elongated cartridge having a writing tip, the cartridge being movable axially within the shell to vary the exposure of said tip with respect to said end opening, and

' oted to move in shell generally transversely with regre es of exposure of the writing tip at said end opening, 7

the cam also'having a plateau angled with respect to said face and having a position of near but not quite completely stable engagement with the follower characterized in that retraction of said cartridge is blocked only when said element is pressed by the pen gripping finger or I thumb of the writensaid plateau facing generally axially endwise to receive endwise thrust transmitted between the cam and follower and to transmit the bulk of said thrust to the shell independently of transrnis'sion to the pen gripping finger or thumb of the writer.

" 2. The invention as defined in claim 1 in which said element extends at one side of said cartridge and is pivspect to cartridge axial movement, said cam being car ried by said element and said follower carried by said cartridge rearwardly vof said spring to engage said plateau only after disengagement from said inclined face, said shell having a portion tapering toward said end opening and said element beinglocated at said tapered portion.

Reterences fitted by the Examiner UNITED STATES PATENTS 1,518,822 12/24 Saadi. 3,075,496 '1/63- Zepelovitclr 120-4203 FOREIGN PATENTS 338,408 1/21 Germany.

L. WILLIAM VARNER, Primary Examiner.

GEORGE A. NINAS, 1a., JEROME VSCHNALL,

I 1 Examiners. 

1. IN A WRITING PEN ASSEMBLY, THE COMBINATION COMPRISING AN ELONGATED SHELL HAVING AN END OPENING, AN ELONGATED CARTRIDGE HAVING A WRITING TIP, THE CARTRIDGE BEING MOVABLE AXIALLY WITHIN THE SHELL TO VARY THE EXPOSURE OF SAID TIP WITH RESPECT TO SAID END OPENING, AND ACTUATOR MEANS INCLUDING A PRESSURE RESPONSIVE ELEMENT MOVABLE IN A DIRECTION TO ADVANCE SAID CARTRIDGE WITHIN THE SHELL FOR INCREASING THE EXPOSURE OF SAID TIP, SAID ELEMENT BEING EXPOSED AT THE SIDE OF SAID SHELL NEAR SAID END OPENING AND IN POSITION TO BE PRESSED BY THE PEN GRIPPING FINGER OR THUMB OF THE WRITER DURING WRITING, SAID ACTUATOR MEANS INCLUDING A SPRING CONTINUOUSLY URGING THE CARTRIDGE IN A RETRACTION DIRECTION FOR DECREASING THE EXPOSURE OF SAID TIP, SAID ACTUATOR MEANS INCLUDING A CAM AND A FOLLOWER MOUNTED SO THAT ONE OF THE CAM AND FOLLOWER COUPLED TO SAID ELEMENT MOVES GENERALLY INWARDLY INTO THE SHELL INTERIOR AS THE OTHER OF SAID CAM AND FOLLOWER COUPLED TO SAID CARTRIDGE MOVES GENERALLY AND AXIALLY WITHIN SAID SHELL, THE CAM HAVING AN INCLINED FACE MOVABLE OVER A RANGE CORRESPONDING TO DIFFERENT DE- 